The female rabbit’s reproductive system is highly specialized, distinguishing it from many other common mammals. It is adapted for rapid and prolific breeding, reflecting the rabbit’s role in the ecosystem. This article explores its distinctive anatomy, reproductive processes, and prevalent health concerns.
Unique Anatomy of the Female Rabbit Reproductive System
The female rabbit, known as a doe, possesses a duplex uterus. This means she has two entirely separate uterine horns, each approximately 7 centimeters long. Each uterine horn features its own distinct cervix, and these two cervices open into a single, shared vaginal canal.
This structure can be visualized like a “Y” shape, where the two upper arms represent the uterine horns, and the single base forms the vagina. The ovaries are situated at the end of each uterine horn, positioned beneath the kidneys. The vagina itself is a relatively large canal, with the urethra joining it approximately halfway along its length.
Reproductive Function and Mating
Female rabbits are induced ovulators, meaning the release of eggs from the ovaries is directly triggered by mating, unlike many other mammals with spontaneous ovulation. This mechanism ensures ovulation occurs precisely when sperm are present, maximizing fertilization chances.
When mating occurs, physical stimulation initiates a neurohormonal reflex, leading to a surge of luteinizing hormone (LH) that triggers ovulation, typically within 10 hours. Does are receptive to breeding for approximately 14 days, with cycles of receptivity occurring every 4 to 6 days.
Pregnancy and Birth (Kindling)
Following successful mating and induced ovulation, fertilized eggs travel down the oviducts and implant within the two separate uterine horns. The developing embryos mature concurrently in these distinct compartments. Gestation typically lasts 29 to 35 days, with most does kindling around day 30 to 33.
As does approach their due date, typically around day 28 of pregnancy, they begin characteristic nest-building behaviors. This involves gathering hay or other soft materials and pulling fur from their bellies to line a warm, insulated nest for their kits. The birth process, known as kindling, sees kits passing from the uterine horns through the individual cervices and then exiting through the single vaginal canal. The doe may move in and out of the nest during this process, tending to her newborn offspring.
Common Health Conditions
Female rabbits are predisposed to certain reproductive health issues, with uterine adenocarcinoma, a type of uterine cancer, being the most frequently diagnosed tumor. Its incidence increases significantly with age, with prevalence rates reaching 50% in does over five years old, and 60-80% in rabbits over three to six years of age. This condition progresses slowly, but can metastasize to distant organs like the lungs and liver within one to two years if left untreated. Early signs include reduced fertility, smaller litter sizes, stillbirths, or a bloody vaginal discharge.
Other potential concerns for the female reproductive tract include pyometra, an accumulation of pus within the uterus, and vaginitis, an inflammation of the vagina. Pyometra can be a severe, life-threatening infection requiring immediate veterinary attention. Due to the high risk of these conditions, particularly uterine adenocarcinoma, spaying (ovariohysterectomy) is widely recommended for pet rabbits not intended for breeding. This surgical procedure removes the uterus and ovaries, eliminating the risk of these serious reproductive diseases.